Project Halo is a long-range research effort, pursuing the vision of the Digital Aristotle— a system containing large volumes of scientiic knowledge and capable of applying sophisticated problem-solving methods to answer novel questions, with applications in education and scientiic research. The current focus of the project is the development of HaloBook — an electronic textbook capable of answering a student’s questions. This talk will summarize the history and motivation for Project Halo, describe the current work on HaloBook, and discuss possible Grand Challenges to motivate future research.